Elastomeric or liquid waterproofing membranes are one of the most convenient methods of waterproofing shower walls before installing tile. These membranes consist of products such as Custom Building Products’ Redgard and Laticrete’s Hydrobarrier and Hydroban and Mapei’s Aquadefense. I will refer to all the membranes as Redgard for the purposes of this post, but they all work nearly the same way.
These materials can be installed with a regular paint brush, paint roller, trowel, or even sprayed on. They are applied to your shower walls then tile is installed directly onto it. When I use these products I always use a cement-based backerboard as the wall substrate without a plastic vapor barrier.
It is imperative that you do not install plastic behind your walls since this would create two waterproof membranes with your substrate between them. Having two barriers this close together leaves open the chance of trapping moisture between them with no way for it to evaporate. This may lead to mold.You must also tape the backerboard seams with fiberglass mesh drywall tape.
The easiest way I have found to install Redgard is, after the walls are prepped properly, start with a paint brush and thoroughly coat all the corners and angles. The membranes are more the consistancy of pudding than paint so don’t be afraid to scoop it out to spread it. You should be used to it after a few minutes.
After all the corners are coated I use a paint roller and pan to cover the walls. Redgard is bright pink – I mean pepto-bismol pink, it almost glows in the dark. This is useful in that when it is dry it turns dark red. The other membranes are similar. Laticrete’s Hydroban, for instance, goes on light green and dries forest green.
Just thoroughly coat the entire inside of your shower until the whole thing is bright pink – enough so it can be seen from space. That’s it – go have an adult beverage until it dries. You must then do a whole second coat the same way. Make sure the first coat has fully changed color before applying the second coat. If you are using a roller Custom (the company that makes redgard) recommends that you roll on the first coat horizontally and the second coat vertically to ensure full coverage. (Thanks for that Davis)
Most of the product specifications for these materials state two coats to be sufficient, and it probably is. I normally use three coats. I’m weird like that. Unless you have a steam shower or something similar, two coats would probably be enough. It’s up to you.
These products shrink a bit as they dry so you must make sure that it has not shrunk enough to create holes or voids in places such as corners and seams. You need a full coating for the product to be effective. When you are finished you should let the walls completely dry for a day before tiling.
Your tile can then be installed directly onto your walls over the membrane with a proper thinset mortar. When these products set they will create a rubber-like coating on your walls that is waterproof. When used on shower walls it is a (relatively) quick, effective water barrier for your installation.
These products can also be used as waterproofing on your shower pans in leiu of a regular pan membrane. Make sure your specific product includes specifications for this application if you choose to do that. Check the respective website for your particular product. I do know you can do this with Redgard, Aquadefense, and Hydroban.
I also use these products for main or additional waterproofing on things like shower niches and concrete wall in basements, places where it is difficult to have a plastic vapor membrane behind the backerboards. Basically any place that does not have waterproofing between the tile and shower framing. I always have Redgard with me. The versatility of these products make them a integral part of my shower waterproofing toolbox.
The only drawback for these products, if you choose to look at it that way, would be the price. They are a bit expensive. You may be able to get better prices by ordering online but make sure you take shipping costs into consideration. You can get a gallon of Redgard online for about $45.00 plus shipping. That should be enough to do a regular tub surround. That is a five foot back wall with two 3 foot side walls. For larger showers you can also get a 3.5 gallon bucket.
Make sure to check the website for your product, they have a load of information for them. As always, if you have any questions feel free to leave a comment for me.
Need More Information?
I now have manuals describing the complete process for you from bare wall studs all the way up to a completely waterproof shower substrate for your tile. If you are tiling your floor and walls and using a liquid membrane you can find that one here: Liquid Topical Waterproofing Membranes for Floors and Walls.
If you are just tiling around your tub or pre-formed shower base you can find that manual here: Liquid Topical Waterproofing Membranes for Shower Walls.
It depends on the amount of moisture being released from the slab as well as the amount of hydrostatic pressure behind it. In 85% of cases the redgard will be just fine – and since you aren’t planning on adhering tile to it redgard will work just fine. Problems could arise with tile installations over what you’ve described because redgard, as well as most liquid membranes, are meant to be installed on the positive side of vapor or moisture transmission. This means the vapor is normally pushing against the membrane which has a solid surface behind or beneath it rather than pushing into it away from the substrate to which it is adhered. KnowWhatIMean?
No need to reinforce the spider cracks unless you think they’ll grow larger than 1/4″. Entirely a judgement call normally made by someone standing in the room.
Yes, it’s overkill. If you aren’t installing tile you will likely be fine with just a good concrete sealer.
Thanks for the great words and advice. We are in the process of building a shower and had planned to use Redgard, but reading your article was incredibly helpful. We’ll do 3 coats as well. Thanks!
Thanks for the quick response Roger. (Its Mark btw
) Do you think the mesh of the electric radiant heating pad will suffice in crack prevention? I would love to save some money…that Redgard is not cheap.
Hey Mart btw,
It may. As long as the cracks are only small (not gapped more than about 1/16″ or so) and there is no vertical displacement – one side is not higher than the other – the mesh should suffice to compensate for that.
Hey Roger- Im working on a installing tile on top of a slab basement foor. There are minor cracks which I will be using redgard to bridge before installing. The homeowner has asked to install electric radiant heating. Is this a problem on top of regard? Great site…thanks for your help
Hey mpsd03 (If that IS your real name
)
No problem at all. Redgard is approved for use as an anti-fracture membrane beneath heating elements.
Hey Roger,
Which is the better route to go, vapor barrier behind the hardi board or redguard over it? I’m inclined to think the redguard would be the better of the two. Also, one of my walls is exterior and insulated, would I have to remove the backing of that insulation behind the hardi board? Thanks in advance for any advice you may be able to provide.
HI Dean,
Redgard is the better method. You will need to at least cut slits in the facing of the insulation to allow vapor to dissipate. You don’t necessarily need to remove the backing.
I’m using Densshield in my shower stall. I plan on using Redgard on the thinset/mesh tape corners, and coating the screwhead areas also instead of filling with silicone…I will not be treating the rest of the Densshield. oes this sound like a good course of action? Thanks, Kevin
Hi Kevin,
Yup, that will work just fine. Make sure to check your redgard after it cures – it has a tendency to shrink a bit. Make sure it doesn’t pull away from the seams you’re trying to cover.
Hi Roger! Great website, thanks for all the great info. Trying my hand at tiling. Here’s my query/question/conundrum…or as my wife likes to call it, my “freakin’ mess”.
I’m putting in a basement bathroom with an alcove tub up against an exterior/foundation cinder block wall. I’ve tested the cinder block for moisture issues and no problems there.
My plan is to use the cinder block 60″ length of wall (nice and flat and plumb with minimal raised mortar seams. A 1944 house and built well, thank goodness!) and frame up the short sides of the alcove and put up CBU panels on the short sides and on the ceiling. Tape and thinset the inside corners and any existing seams and then put three solid coats of Redguard on the whole thing to create a waterproof tub/shower enclosure.
Then put up some porcelain tile with modified thinset. I realize the outside wall may get a bit cool during the winter (only gets cool to the touch but not COLD if you know what I mean?), but aside from that, do you see any problem with my plan? Trying to avoid furring out the wall due to space constraints.
Thanks for the info! You rock, Dude!
Hi Julian,
Your freakin’ mess sounds good to go. I would make sure you first mix up some redgard ‘primer’ (one part redgard to three parts water) and roll or brush that on the backer and cinder block first to seal up the pores real well and allow the redgard to do it’s job better.
Thank you very much. You are a wealth of information and I’m sure I speak for many when I say that I’m glad you’re not stingy about sharing your knowledge.
Roger,
I saw you had a guide….’TILE TIPS OF THE RICH AND FAMOUS’
I should do that…I’d call mine “TILE ADVICE OF THE POOR AND INSIGNIFICANT”….
Think it would sell?
Hell yeah it would sell! You ever seen how many people watch over-reactive drama queens (men) fight over who can spend the most ridiculous amount of money for shit people leave in a storage locker? Yeah, people will buy anything. That’s why business people such as ourselves should have ethics, much of the general public has none.
Joe, have 27 years in the tile union. Am a tile setter. Have used red guard and other manufacturers products, i.e. Hydroment Blacktop and Ultraset. Is redguard compatible with epoxied surfaces and aluminum? I’m considering products to repair my aluminum boat that has pinholes from corrosion prior to me getting it. I’m repairing the pinholes with ‘Marine’ JB Weld, but want to put a coating over it before I install a new wooden floor above it all. My experience and understanding of redguard is that it must impregnate and bond to all substrates. Am I correct? If so, it would not bond to the epoxy or aluminum?
Hey Ray,
I will bond to the aluminum partially, but not to the epoxy in any workable fashion. Redgard is not a ‘wear-surface’ membrane, meaning that is is made to have something installed permanently directly to the surface of it. If not it may tend to curl or completely dry out and crack eventually (when exposed to air long-term). It also does not tolerate abrasion – it is easily scratched, dented and peeled, all of which will compromise the waterproof properties. Don’t think redgard will solve your problem in that application. Sorry.
Ray,
Roger is completely correct…as usual.
There is a spray on rubberized product ( AS SEEN ON TV )…LOL, that will seal small pinholes very well. My dad ordered it and used it on a jon boat and said it worked fine….and he’s 71 years old.
Here is the website – https://www.tryflexseal.com/?tag=im
Can we use Redgard over green board? Also, hubby used plastic vapor barrier underneath the greenboard. Is this ok? It is for a tub/shower surround to be tiled. Thanks so much for your help.
Hi Anne,
Nope, redgard is not approved for use over greenboard (or any drywall) inside a wet area such as a shower, that needs to be cement backerboard. Also, if you use redgard you’ll need to eliminate the vapor barrier. It is one or the other, never both.
Victim of mold illness (mycotoxin) from improperly built shower. Drywall was used under tile on kneewall and grout was not sealed. I don’t know if moisture got in through the 1/4 inch grout or the open seam that eventually developed. Would love to have an idea. Please excuse my ignorance!
I am searching for information on how a shower should be properly built so I know what to ask and look for with contractors. I am not very adept at this stuff. I am getting that concrete board will absorb moisture but can also release the moisture? If a mositure barrier (and why do some sites recommend felt? it seems like that would mold) is behind the concrete board then how does any moisiture that could be in the board evaporate? If there is unsulation on an outside wall that the shower shares, same question.. and wouldn’t the insulation also develop moisture issues? Is there a more preferred insulation if an exterior wall such as pumped in foam? Would it be advantageous to create a moisture barrier on the inside of the drywall backing the concrete board so not directly sandwiched to the concrete board but protecting the drywall backside?
Is it best to put the moisture barrier directly on the concrete board? Use epoxy grout and then seal with what? Then.. if moisture still gets through the grout and tiles, where does it go to evaporate if there is a moisture barrier on top of the concrete board?
As for condensation issues between indoor and outdoor air that might justify a barrier behind the concrete board.. how often and when most likely is that an issue.
Thank you so much! I am so worried about this since being very sickened for many years now from the mold that was growing hidden behind the tiles, which seemingly ate through the drywall and into the wood studs. I don’t understand how to spores-toxins made it out except through the back wall into air flow or the seam but I am definitely sickened from it and test positive for stachybotrys mycotoxions in my body.
A tub enclosure is probably the smartest move for me, but would still like to be able to have a nicely tiled shower in master bath and may have to go that route esp if we purchase a new home.
Install concrete board, tape and apply thinset mortar to the seams, install an approved moisture barrier ( like Redgard ), and then apply thinset mortar and tile ( porcelain finished tile is waterproof ) and if you use epoxy grout ( also waterproof ) then you do not need to seal it.
Cement based grouts are NOT waterproof and thus need to be sealed. Often times the tile contractor will not seal the grout unless it is specifically in the contract that he/she is responsible to do so.
It is always a good idea to use an approved waterproof expansion joint ( 100% commercial grade silicone ) in the seams where 2 planes meet ( any inside or outside corners ) so that they can expand and contract without cracking and are waterproof. Most manufacturers make siliconized grouts that match the cement grout and are usually used in corners.
Thank you, Joe. Is grout sealing very effective or another protective layer to add that cannot be completely relied upon? I will be going for the epoxy for extra measure, but interested about grout sealer just in case.
The silicone is places where the seams meet and the butt up against each other? One on top of the other at the corner before they are places together or after? Makes sense possibly do do both before and after. Or is there a space left in between where the silicone goes? I read on board about using silicone with densguard leaving a space between where the corners meet to put the silicone because if water gets into that joint, it can get back into gypsum material in the middle. Do you have thoughts on densheild?
I found FloorElf’s excellent pdf on shower installations. Many of my questions were answered there. I am still wondering about external walls and insulation. Do you leave the insulation out as extra precaution for water leaking past membrane on top of concrete board or is sprayed in foam a better option? Why dont people use steel studs behind showers as well and densguard or denshield on shower walls and behind them for that matter? As bathroom walls as well? I don’t see paper faced drywall in bathrooms at this point know that I know interior of walls can be effected as well as exterior.
After being deathly sickened by toxic mold growing in shower kneewall, I may be in overkill overdrive, but this is also not something to play around with. To poster above me, I would never tile over greenboard with or without a membrane out of sheer fear. The dryall gypsum is a breeding ground for mold, esp stachybotrys which loves damp cellulose material.
Thank you!
I meant densheild or densarmour on shower walls that are placed behind the studs opposite side of shower (do not know correct terminology) not in place of concrete board and for bathroom walls in general, esp around, near shower. The denshield like products concern me for tile installation.
Hi R – if that is your real name.
Moisture got through your tile and grout because tile and grout are not waterproof. Sealer would not have helped. A shower should be completely waterproof before a piece of tile is even touched. The problem was that your shower was not waterproofed and installed directly to drywall.
A topical waterproofing is always a better option since your waterproof barrier lied directly beneath the tile – no substrate will ever see water with that method. Any normal moisture which gets behind tile (and it will) either evaporates back through the grout lines or runs down behind the tile into the basin or drain. Some sites recommend roofing felt because it is actually a proper moisture barrier – when wet the pores will actually swell and close.
Have you downloaded my waterproofing manual? It’s free and full of proper installation information. If you read it you’ll likely know more than most ‘installers’ claiming to be professionals. You can find it here. Read through that and come on back with any more questions you have.
Can I use Deck Mate Evercote screws to install Durock to my bathroom? I understand that the cement is acidic which is why I am asking. Thanks.
Hey John,
The alkali base in the thinset will not harm coated deck screws. They will be fine there.
Finally getting to the tiling stage of an eternal bathroom project. Only planning to use Redgard on the CBU seams and around 3 niches – two pre-fab, and one custom made.
Two questions:
I bought my Redgard a few years ago, have never opened it, and am just now getting around to needing it. Does it have a shelf life? The Custom Building Products website has a tech data sheet on it that says it has an “indefinite” pot life. Is this the same as shelf life? I hate to think about it being no good, as pricey as it is.
The application instructions on the product do not mention using a brush (though you do in this article). I don’t know how else I’d get into the niches – especially around the sides of them. Is brushing it on not as good for some reason? Just curious why they only suggest roller, trowel or sprayer.
It talks about how many mils it should be when wet and dry. How does a person measure this? How do you? Or do you just do a couple or three thin layers and call it good?
Thanks for the resource!
Hey Christopher,
If I remember correctly redgard has an indefinite shelf life as long as it has not been exposed to air (you haven’t opened it). Pot life is not the same as shelf life. Pot life refers to the amount of time once opened or mixed that a product remains workable from the container. For instance: most thinsets are only workable for 2-3 hours once you mix it.
I don’t know why they don’t recommend a brush, probably because people tend to not get it thick enough using only a brush. The thickness you want is about as thick as a credit card. It is not three thin layers – it’s three thick layers. You can order a wet-gauge which will tell you exactly how thick it is, or you can just use three fairly thick layers.
Also, if the RedGard was exposed to freezing temperatures, it is probably no good.
If the appearance is like pudding…it is ok.
Sorry Roger, actually we have Dens Armor Plus in our shower … it says on it that it is moisture resistant, are you familiar? … should I use Redgard everywhere or only in the corners/seams of walls?
Seriously thank you so much for your time and help. … dunno what I would do without this blog!
Yes, you need to use it everywhere. Densarmour is not waterproof. Use the redgard or switch that for densshield. If you do that you don’t need the redgard at all.
Quick ? for you Roger … after reading all the comments above if you have Dens Shield in your shower you only need to apply Redguard in the corners of the shower correct? Anywhere else you would recommend? Under/Around the showerhead? Thanks so much for your time.
Megan
Hi renovating my bathroom and building a shower stall which will be tiled with 12x12ceramic tiles floor to ceiling. My question is…if I build the shower pan in this order from bottom to top will it hold up….3/4 subfloor – tar paper – wire – mortar – cement board – redgard coating – thinset – tile. Thanks for your help.
Jenny,
They say a picture is worth a thousand words…so here is a link to a website showing pictures and descriptions of step by step construction of a shower on a wood subfloor.
http://www.ontariotile.com/preslope.html
I agree with every step of this…except for minor things such as I do not use an acryllic admix in my deck mud/dry pack.
They used concrete board on the walls and a pan liner over a pre-slope.
It should be very beneficial for your project. Of course, Roger is always available for your follow up questions.
I hope this helps.
HI Jenny,
Do you mean you want to use cement backerboard on the shower floor? If so, no, it won’t last. Read through this to see how to build a proper shower floor: Building a shower floor for tile
Roger,
Would it be insanely overkill if I put Redgard over drywall, and then added Kerdi?? I read most of the stuff on here last night, and you say redgard is easier to use, but then I’d have to use backerboard. Currently we have the all-in-one fiberglass/acrylic tub and surround. I’m suspecting the whole wall is drywalled, so if I could just leave it alone, that would be great. Since the Kerdi is more difficult, and has more room for error, I thought I could mitigate my own potential shortcomings by doing both. Thoughts?
I doubt that you will find drywall behind the tub enclosure.
Usually, you install the tub enclosure/shower and then drywall from the lip of the enclosure on.
If your intention is to construct a tiled shower in the space, I would highly recommend that you don’t use 2 layers of waterproofing. I would either use RedGard over concrete Wonderboard with Custom thinset mortar and grout ( to qualify for their written lifetime warranty ) or use Kerdi. Either, installed correctly, will give you a waterproof shower.
I would not install two different layers of waterproofing on any surface, as it could result in a “moisture sandwich”.
If the Kerdi ever failed – ( pinhole etc ) the moisture would seep in and remain between the Kerdi waterproofing and the RedGard waterproofing….and vice versa were the RedGard on top and Kerdi beneath.
I think Roger will agree that it is unnecessary.
And yeah, Joe’s correct. I missed the surround part of your question. Highly unlikely that there will be anything but the open wall cavity behind it. Just choose one or the other, kerdi or redgard, not both.
Hey Derek,
Just use kerdi. There really is no testing that has been done (of which I am aware) that determines whether or not the two together will last long-term. Kerdi works perfectly, don’t complicate things and potentially cause problems trying to overkill your installation. Trust yourself – if the kerdi is going to have a problem in any areas you can plainly see where and why as you install it.
Hello,
The Custom Building Products Technical Bulletin for RedGard doesn’t mention “Denshield”, apparently “Engineered to prevent damage to the sub-floor or wall cavity if moisture seeps through grouted tile, DensShield® Tile Backer is the first backer board with a built-in moisture barrier. It integrates a moisture-resistant core and microbial barrier* with fiberglass mats and a unique heat-cured acrylic coating.” If Denshield has a “built-in moisture barrier”, then applying Red Guard or similar would possibly trap moisture between the barrier of Denshield and the Red Guard. Is that correct?
Thanks.
Hey Art,
That”s because denshield is a waterproofing product, a different one. They should not be used together – they are two entirely different forms of the same thing – waterproofing. The board by itself, when properly installed, creates a waterproof substrate for tile – no redgard needed. Another reason they really shouldn’t be used together is not really the moisture barrier issue, but the possibility that the redgard may or may not last long-term over the face of it, since you are essentially painting a waterproofer onto a waterproof substrate. I don’t believe it’s ever been tested because there is no need to have both products on the same wall. One or the other.
Art,
The seams and fastener perforations, of course, are not waterproof and need to be sealed according to the manufacturer’s specifications ( to obtain warranty ).
Roger, have you heard much feedback on this product?
I have known several contractors that indicated it had failed ( almost always as a result of moisture within the wall cavity or improper sealing of the joints and fastener perforations ).
I also know Bud Cline swears he sealed a piece in water for a year with no issues at all….
Yup, I’ve used it a few times and never had problems with it. I run a bead of silicone over every edge before stacking the next then rather than screwing it in and sealing the holes I’ll place a dot of silicone on the board and screw right through it. Seals the hole as you screw in the fastener. I don’t know that I would seal it in water, or even use it in any type of commercial or steam application, but from my experience it works just fine in normal residential applications.
I think JB is referring to foil backed insulation, such as is often installed on basement walls when folks have a walk out basement.
I am guessing JB has foil backed insulation ( fastened directly to the slab wall ), then a stud wall which is being used as one of the shower walls.
Batt insulation specifically designed for the interior of foundation walls often has a perforated poly facing that prevents air from circulating through the batt, but allows water vapor from the wall to escape. The foil face ( often fiber foil ) is designed to do the same thing an emergency blanket does….reflect radiant energy.
If it were my shower, I would apply RedGard to the face of the CBU ( concrete board ) just beneath my tile. If it is applied according to the manufacturer’s specifications ( for waterproofing – apply it 47 mils thick when wet and it should dry to 30 mils thick – as a shower pan liner it needs to be applied 93 mils when wet and should dry to 47 mils thick ), it will create a waterproof shower that has a perm rating of 0.06 and a water vapor transmission rate of 0.02 grains/hr per ft squared.
I am often asked how do you know when you have the thickness right and aside from spending a lot of money on a contractor’s fancy tools, you can buy a simple metal wet film thickness gauge for only a couple of bucks…here is a link for that:
http://www.dynesonline.com/wet_film_thickness.html
I hope the info helped, JB.
The sales guy at the tile shop is telling me this product is designed to be used on Sheetrock curious why you discourage.
Hi James,
Because there is no industry standard that supports the use of a liquid membrane on drywall in a wet area. The only waterproof membranes approved by the NTCA over drywall in a wet area are all sheet membranes such as kerdi, no liquids at all.
Oh, and if the sales guy is telling you it was ‘designed’ to be used on sheetrock you can tell him it was actually designed as a crack-suppression membrane over concrete, not as a waterproofing membrane at all.
Although properly applied, it is actually approved for use in steam showers.
It is a good product….IMHO
Applied over a proper substrate is is a good product for any shower, Joe. But it must be applied correctly over an approved substrate.
That is absolutely correct, as the approved substrates I have listed below indicate….and as you said, they don’t include drywall.
Well,
Custom Building Products Technical Bulletin for RedGard states on Page 1 under #3:
Substrates suited for RedGard include:
• Concrete, cement mortar beds, masonry
• WonderBoard® , cement backerboards
• Exterior grade plywood — For crack isolation of interior dry areas only
• Exterior decks — Contact Technical Services for information related to exterior applications and the use of pressure treated wood decks
• Lightweight concrete
• Gypsum based cement topping ( this is applied to floors as a leveler and also when adding radiant heat piping on top of a concrete slab )
You shouldn’t be putting drywall in a shower….and this doesn’t list drywall, so at your own risk,,,no warranty seems to be the message. Then again, you have the opinion of the counter help at a tile store.
If he was a good tile setter….do you think he would make more money tiling or running a register?
Just sayin….
http://www.custombuildingproducts.com/docs/TDS104_RedGard_3_11.pdf?user=diy&lang=en
Thanks for the help Joe.
But!
People coming here for information are simply homeowners who know next to nothing about the products or methods they are asking about, let alone how much bad information is thrown around due to improper training, incompetence, or merely people not giving a shit. Unlike us they do not look at these people as someone who probably has no idea what they are selling, to my readers these people are supposed to know what they’re doing.
Feel absolutely free to give advice to commentors here but please refrain from assuming people giving them advice used to be tile setters or are purposely giving improper advice. They may simply not be trained correctly and it really accomplishes nothing. For the record, for seven years redgard DID state that it was approved for use over regular drywall. However, when they began to have failures and could find no way to place it on the shoulders of the installers, they redacted that recommendation and no longer allow it. Guess they figured out it didn’t work.
I have worked been a union trained tile mechanic for more than 25 years and more than 10 as an instructor, training tile apprentices for a local trade college as well as Job Corp. I have made a good living correcting expensive and improper installations, like some of the ones you are trying to help folks avoid.
My most humble apologies for any confusion. It wasn’t my intention to imply that the counter person was a former tile mechanic…rather that IF they were…would they be running a cash register or installing tile > meaning that they most likely are NOT trained tile mechanics.
I also did not mean to infer that the flooring store employees were purposely giving improper advice. The fact is that most salesmen/women in flooring stores have never installed flooring and all too often they have had minimal training….and the public should be cautious with their recommendations, though well intended.
Again, my apologies if that wasn’t sufficiently clear in my message.
My point was simply that:
Custom tile installations are expensive things, at least the ones I do, and I would tell anyone spending thousands of dollars to talk to a professional. Use the Free clinic or the Mayo clinic…there really is a difference. Your 17+ years experience qualifies you as a Mayo clinic kind of guy…lol
Like you, I have a lot of respect for true tile installers, who are at the top of their game, and who take pride in their work. I have trained dozens of them who have gone on to prosperous and deserved careers. That said, if I had a nickel for every time a customer said…”But the guy at the tile store said…”…LOL.
It just always strikes me funny when people hire a person with more years of REAL experience in their field than your average brain surgeon….but the flooring store employee gave contrary advice….so.
My brother in law used to give me stock tips…..I own 5 homes and he still owns 1.
I took the advice of an expert.
Your readers have three resources that I didn’t have when I came into the business 25 years ago….still FREE advice based on your 17+ years of experience , the internet, and technical bulletins that are so easily viewed.
They should take full advantage of all 3 because it gives them something that I charge for….years of training and field experience as, what we union guys call, a tile mechanic.
As to what is a proper installation method, inevitably manufacturers retain the final say in the products capabilities and approved methods for it’s installation. TCNA and ANSI aside, even building inspectors will defer to the engineering specs for products they are unfamiliar with.
BTW, Custom also modified RedGard’s application methods ( spray application and mil thickness ) during the years it has been out. That is not all too uncommon a practice, for manufacturers, as “field” installations demonstrate weaknesses and strengths that they did not foresee.
I see that you seem to like it and I do, as well.
I must, I have more than 30 gallons of it on hand.
Keep up the good work. I’ll wager you have save a lot of homeowners a lot of money by providing free and professional advice.
Again, forgive an old mud man if I ruffled any feathers. It truly wasn’t my intention.
P.S. – When you do write that book, let me know….I’ll buy a copy if you autograph it.
Hell, no ruffled feathers here Joe. I appreciate the help. I just want to make sure it’s not another person who inevitably only demeans people giving incorrect advice. As much as I can’t stand it either, it isn’t always their fault. A lot of people giving ‘advice’ on the internet mainly look for someone at whom to point a finger rather than solve the problem. They should be politicians.
Feel free to hop in wherever you wish.
I hear ‘but the guy at the tile store said…’ almost as much as I hear ‘he said he’s been doing it this way for 15 years…’, they both irritate the hell out of me. Of course, if you haven’t yet noticed, I tend to be a bit opinionated.
My friend, anyone who has 18 years of true field experience, in any profession, earned their opinion…and it would pay folks to heed it.
Hi,
I guess if I have foil behind one of my walls , it would not be a good idea to use Redgard on the backer board on that same wall, same as with plastic?
Hey JB,
I wouldn’t. but then I normally don’t run into walls with tin foil or plastic behind them.
Probably not a good idea, though.
JB,
I posted some info for you but it ended up at the top of the list of comments…so I wanted to alert you that it’s here for your consideration.
hi roger,
i am about to install tile on shower walls. I am going to apply Redgard over cement board and then 12″ tile.
My questions are:
Ceramic or porcelan tile?
modified or unmodified thinset – if modified which one exactly and please, if you can, recommend brand from Home Depot or Lowes
epoxy grout ok?
after all that what sealer do i use?
Thank you so much…….
Hey Alex,
Porcelain tile is ceramic tile.
Read through this to help you make the right choice: Choosing the correct type of tile
Modified thinset – Versabond from HD works very well.
Epoxy grout is fine.
If you use epoxy grout do not use sealer – it’s not needed. If you don’t use epoxy, use Miracle Sealant’s 511 impregnator – it should be available at HD as well.
Hiya, Roger-
First off, thanks very much for this wonderful resource. I am a do-it-my-own-darn-selfer and have learned quite a bit from just a few of the articles you’ve written.
Secondly, how egregious a sin is it that I mistakenly used plain old mesh tape (the plastic kind- WallSpan brand) on the seams for the HardieBacker I put up around my new tub? I used the thinset that I’ll be using for the tile, but didn’t realize that the mesh was not alkali-resistant. Do I need to scrape and redo?
Third, if I do need to scrape and redo, can I start tiling while the thinset on the tape is still wet or do I need to wait for it to completely dry before topping the backer board with my tile?
Thanks very much again, sir, and have a splendid day!
Regards,
Karim.
Hi Karim,
It’s not absolutely imperative that you’ve used that tape. It’s more dire in applications such as steam showers.
If you do remove it you can do it as you set the tile – it doesn’t need to be cured first.
Excellent news, Roger. Thanks very much!
If you have any accounting questions, let me know
Karim,
If you used that tape and then put multiple coats of Redgard on it, setting it not only into the backer-board but making it part of the waterproof membrane, you are fine. The Redgard protects the tape from the thinset mortar…hence – no issue.
I have been tiling 25 years and have built showers with 14 shower and body sprays…believe me, I would know.
my tiles aren’t going all the way up to the ceiling and I was planning on using drywall compound on the ceiling and above the tiles. can i use the redgard over or under drywall compound there or should I still be using thinset? I thought thinset only had to be used under the tiles inside the shower. What I’m talking about is above the shower area. I wanted to redgard it to make certain it was mold resistant (I’m using dense shield there) as well as giving it a waterproof membrane. please tell me what you think.
Hi Peg,
If you have densshield up there you don’t need to use a membrane to make it mold-resistant – it already is. You can use drywall compound on it. Just make sure you use the powdered stuff you mix with water and not the pre-mixed stuff, which may re-emulsify.
Hello. I have a question. We recently had our kitchen floor tiled and over the subfloor our contractor put down RedGard instead of a thin set before laying down the hardi backer. Is this a common practice? I have been told that if no thin set is used is voids the warranty on the hardi backer and we have a greater chance of the tiles cracking due to movement of foundation as we basically have a free floating floor at this point. The tile we picked out is rectified tile which is so uneven on the floor and you can not walk in bare feet on our floor right now as the edges are sticking up really bad in a lot of places. Our contractor says it can’t be even because we have uneven floors (I thought all were) and we picked the wrong tile due to the edges being so sharp. Can you please give me your opinion on this?
Hi Julie,
My opinion? You’re tile contractor doesn’t know how to lay a flat floor. Rectified tiles are made by cutting to size after they are fired – this gives a perfectly consistent size and they should be able to be installed perfectly flat. What you have is called ‘lippage’, it is a sign of an inferior or non-professional installation. No tile should stick up or sink down from the tile next to it. There is an acceptable amount of lippage but we’re talking about 1/32″ – nothing you would ever notice.
Not sure why he would install redgard beneath your backer. If used for the purpose of waterproofing or as a crack-suppression membrane it needs to be installed directly beneath the tile – always. All floors are uneven to an extent. We flatten them out as we install the backer and as the tile is installed. Rectified tile HAS to be installed flat due to the square edge. It is not an excuse for poor installation – it’s made specifically to be installed flat.
No thinset will void your warranty and may cause cracked grout/tile from inadequate support. From what you’ve described it is simply a very poor installation. Wrong products, wrong use of products, missing steps and excessive lippage. It is my opinion that your contractor is attempting to cover his ass by throwing inaccurate excuses at you.